1. Field of Invention
This invention is related to a method for testing a semiconductor device. More particularly, the present invention is related to a method for retesting a semiconductor device by taking back the semiconductor device which is disposed on the carrier to perform the retesting steps.
2. Related Art
After completing the manufacture of a wafer, the wafer is needed to be entered into assembly and testing steps so that the semiconductor devices provided in the wafer is able to be separated from each other, disposed on and electrically connected the motherboard. Therein, the assembly steps include the steps of wafer dicing, die attaching, wire bonding and encapsulating. However, the semiconductor devices may be damaged, destroyed or not connected well to the motherboard. Thus, the testing steps following the assembly steps are usually required so as to verify whether the function of the semiconductor devices are performed well.
According to the requirement of products, the testing steps may be performed either before or after assembly steps. As shown in FIG. 1, a wafer 1 is placed on a film frame 222, wherein the wafer 1 has a plurality of semiconductor devices 10. The wafer 1 is entered into testing processes through a tester, wherein the testing processes include the visual inspection and signal testing. After each semiconductor device or chip 10 is finished testing, the testing result will be recorded in a wafer map. Then, the chips or semiconductor devices 10 placed on the film frame 222 will be taken out and then placed on chip carrier such as Gel Pak according to the testing result recorded in the wafer map through a pick-and-place machine. Generally speaking, the testing result may divide the semiconductor devices or chips into two or more groups in different degrees. Different groups in different degrees may be placed on different carriers. For example, the chips or semiconductor devices 10 may be divided into two groups. One is qualified for shipping-out and the other is disqualified for scraping. The pick-and-place machine, according to the testing result recorded in the wafer map, will take the good chips out and then place them on the carriers so as to ship the good chips out. However, the disqualified ones will leave on the film frame 222 to be under scraping processes.
As mentioned above, if the good chips placed on the carriers are required to be divided into two different groups in different degrees, the good chips are usually not able to be placed in the tester again so as to cause such good chips to be scraped. In addition, when the yield rate of the chips are low, it is usually required to take out the chips disposed on the film frame 222 which are originally regarded as disqualified ones but not far away from the qualified standard so as to increase the yield rate. However, the tester is not able to perform the testing processes on the chips left on the film frame 222 so that the testing processes are not usually performed well.
Therefore, providing another testing method to solve the mentioned-above disadvantages is the most important task in this invention.